Amid controversies over the danger of electronic cigarettes, Philip Morris Korea has released its new research data, claiming its product IQOS contain 90 percent fewer harmful chemicals in its steam than conventional cigarettes.

The tobacco company also promised to disclose raw data used for the new study in a phased way by the first half of next year.

Philip Morris Korea unveiled its latest research on heat-not-burn cigarette IQOS at a news conference at Four Seasons Hotel in Gwanghwamun, central Seoul, Tuesday.

Heat-not-burn cigarettes, also called e-cigarettes, heat tobacco without combustion, which makes users inhale steam, not smoke. Philip Morris was the first to bring smoke-free heated tobacco to Korea, followed by British American Tobacco’s Glo and KT&G’s Lil.

According to Philip Morris Korea’s study, IQOS resulted in 90 percent (95 percent in carcinogens) fewer substances out of 58 harmful chemicals, including 18 hazardous compounds and 15 carcinogens labeled by the U.S. FDA. The company also said its e-cigarette produces 90 percent fewer toxic substances than conventional cigarettes.

With the latest study, the company backs up its claim that e-cigarettes are less harmful than regular cigarettes. The company said it would prove how a reduction in toxicity in e-cigarettes affects human body with a long-term observational study.

“The new study needs multi-phased tests to confirm the reduction of risks in total,” said Mikael Franzon, senior medical adviser to Philip Morris International. “Measuring the reduction of harmful substances and confirming lowered toxicity is one of the steps to secure proofs that the company is seeking.”

According to Franzon, Philip Morris is conducting an animal test to check how much risks IQOS can cut. After a long-term clinical trial, the company needs to measure how the e-cigarette helps reduce risks for long-term users, Franzon said. Then, the company will be able to announce that IQOS results in lower risks officially, he added.

To get IQOS approved as a modified risk tobacco product (MRTP), Philip Morris submitted 2.3 million pages-long clinical trials data to the FDA in November last year.

However, whether heat-not-burn tobaccos reduce hazardous substances or do more harm than good is still controversial. Critics say the evidence is weak to back up makers’ claim that e-cigarettes are less dangerous than conventional products.

According to a report in JAMA Internal Medicine by Dr. Reto Auer of the University of Bern in Switzerland, IQOS released three times more of cancer-causing chemical acenaphthene than traditional cigarettes. Heat-not-burn cigarettes also released other chemicals linked to cancer, including carbon monoxide, volatile organic compounds, and polycyclic aromatic hydrocarbons.

A Japanese academic group for smoking cessation also said in April last year that IQOS emits harmful substances just like regular cigarettes and smoke-free e-cigarettes might raise the risk of secondhand smoking.

In Korea, the public demands more studies on heat-not-burn cigarettes. Some international experts point out that credibility of studies affirming e-cigarettes is questionable since Philip Morris subsidized them. Others say IQOS supporting studies are just claims by Philip Morris researchers.

Philip Morris Korea’s corporate affairs director Kim Byung-chul said the company was fully aware of credibility issue on a tobacco company.

“We’re searching ways to overcome this issue. We have released our latest study results. In early next year, we will disclose raw data of the study. It is very rare to release raw data in this industry,” Kim said.

The Ministry of Food and Drug Safety said it would analyze heat-not-burn products to assess how they reduce harmful chemicals. Philip Morris recently submitted its study methods and partial data to the ministry.